Three-dimensional filet stitch fabric wall reinforcement

ABSTRACT

The invention concerns a fabric made with biocompatible material filaments, shaped like an open-mesh unblocked weave forming, in the laps constituting, respectively the front (AV) and rear (AR) walls of the fabric, substantially polygonal cells providing the fabric at least in two perpendicular directions with substantially balanced dynamometric behaviour, said laps in the front and rear walls being linked by a bracing. The invention is characterized in that the bracing is provided by monofilaments of one of the laps forming one of the walls (AV and AR) of the reinforcement, each of said monofilaments forming, after a constant number of rows of meshes in its lap, a mesh (M) with one of the meshes (m 3 ) of one of the laps of the other wall (AR and AV) of the fabric.

The invention relates to a three-dimensional open-worked fabric wallreinforcement useful, for example, in parietal and/or visceral surgery,but capable of being applied to other fields of surgery.

French patent application FR-A-2 779 937 already discloses anopen-worked fabric formed by monofilaments consisting of a biocompatiblepolymer material, such as polyester, polyamide or polypropylene, whichare worked in a weave with open unblocked meshes which, in the lapsforming respectively the front and rear walls of the fabric, form aplurality of cells of substantially polygonal shape. These cells givethe fabric a balanced dynamometric behavior, that is to say offeringsubstantially the same resistances to elongation and the samepossibilities of elastic return at least in the two main directions, tobe precise longitudinally and transversely.

In practice, the lap or laps forming the front wall of the fabric is orare connected to the lap or laps forming the rear wall by means of abracing composed of one or more laps, of which the meshes engaged withthe meshes of the front and rear walls are connected by means of longfloats.

It becomes clear that, in this type of fabric, the floats of the bracingreduce the elasticity and resistance characteristics differently in thetwo main directions and therefore adversely affect the desiredisoelasticity.

Moreover, the presence of this or these connecting laps increases themass per unit area of the fabric and, if they are produced bymonofilaments, tends to reduce the conformability and flexibility of thefabric, whereas, on the contrary, parietal repair surgery requiresflexible and porous fabrics with a low mass per unit area.

The object of the present invention is to provide a wall reinforcementwhich overcomes these disadvantages and the fabric of which has the sameresistance and elasticity characteristics longitudinally andtransversely, while at the same time improving its flexibility andconformability, without affecting its low density and high porosity.

For this purpose, in the wall reinforcement according to the invention,the bracing of the laps forming respectively the front wall and the rearwall of the fabric is ensured by means of the monofilaments of one ofthe laps composing one of the walls of the reinforcement, each of thesemonofilaments forming, after a constant number of rows of meshes in itslap, a mesh with one of the meshes of one of the laps of the other wallof the fabric.

Thus, for example, one of the two laps composing the front wallcomprises, at regular intervals, meshes engaging with the meshes of oneof the laps of the rear wall, in order to ensure the connection and holdof the two walls.

By means of this arrangement, not only is there no additional lapbetween the laps forming the front and rear walls, but there are also nolonger any floats between these two laps, such floats possessing a morelimited elongation capacity than the meshed structure obtained.

Moreover, each monofilament portion extending between the mesh formed inthe front wall and the mesh formed in the rear wall ensures an excellentstability of these two walls by virtue of its stiffness or rigidity andthus makes it possible to limit the number of meshes forming a brace,while at the same time avoiding influencing the dynamic characteristicsof the reinforcement obtained.

The invention will be understood more clearly from the followingdescription, with reference to the accompanying diagrammatic drawingillustrating an embodiment of a knitted wall reinforcement according tothe invention.

FIG. 1 is a partial cross-sectional side view illustrating a fabric withbracing by means of an intermediate lap,

FIG. 2 is a cross-sectional side view of the fabric according to theinvention,

FIGS. 3 a and 3 b illustrate, for an embodiment of the fabric accordingto the invention, a diagram of the connection of the two laps formingrespectively the rear wall and the front wall,

FIG. 4 is a front image of a fabric according to the invention, taken bymeans of scanning electron microscopy with a magnification of 20.

In FIGS. 1 and 2, the mesh columns AV and AR each indicatediagrammatically the two laps of meshes formed on a double-sectionRachel loom by means of monofilaments of a biocompatible material and,for example, polypropylene monofilaments.

In FIG. 1, the connection between the front and rear walls is ensured bymeans of an intermediate lap N alternately forming, every six rows, onemesh ml on one of the laps of the rear wall of the fabric, then one meshm2 on one of the laps of the front wall, before a float F is formed onthe following six meshes, until the next mesh ml is produced.

Of course, this connection is made in various columns of the fabric,and, for example, every two columns, with an offset of the rows in whichthe loops m1, m2 are formed.

This FIG. 1 illustrates the current structure of knitted reinforcementsand makes it clear that, during the stretching of the laps, the longfloats F have little possibility of following the elongation movement,at all events less than a mesh, the loop of which can close on itself toproduce thread, and therefore contribute to alerting the dynamometriccharacteristics of the reinforcement.

FIG. 2, which corresponds to the fabric according to the invention,shows that the connection of the front AV and rear AR walls is ensured,for example every two columns and every six rows, by one of themonofilaments 2 forming one of the laps of one of the walls and, forexample, of the front wall AV, this monofilament forming a mesh M on amesh of one of the two laps composing the rear wall AR. As a result ofthis, and with the exception of the portions 2 a of monofilament 2extending between the two walls of the fabric, there is no otherelement, such as a float, between these two walls.

As a consequence, in the event of stretching and even of elastic return,the meshed structures of each of the two walls AV and AR are not impededby float threads, and the connecting portions 2 a, arrangedtransversely, are more capable of following the movements, at the sametime tolerating the tightening or loosening of the meshes which theyconnect between the two walls.

FIGS. 3 a and 3 b illustrate the connection screens of the two lapsforming respectively the rear wall and the front wall of a fabricaccording to the invention, produced according to the following scale.

Front wall:

-   -   lap a) 0.1.1.1/1.2.2.2/3.4.4.4/5.4.4.4/4.3.3.3/2.1.1.1//    -   lap b) 5.4.4.4/4.3.3.3/2.1.1.1/0.1.2.1/1.2.2.2/3.4.4.4//    -   Rear wall:    -   lap c) 4.4.5.4/4.4.4.3/3.3.2.1/1.1.0.1/1.1.1.2/2.2.3.4//    -   lap d) 1.1.0.1/1.1.1.2/2.2.3.4/4.4.5.4/4.4.4.3/3.3.2.1//

This fabric is produced with polypropylene monofilaments having adimension of between 0.07 and 0.14 millimeters, preferably 0.08 or 0.10millimeters, said dimension combining fineness, strength and stiffnessperfectly. The filaments are worked in a weave of the Atlas type,forming locally a mesh M on some needles of the rear structure,simultaneously with the formation on these needles of meshes m3 formingone of the two laps of the rear wall.

This weave makes it possible to produce the fabric appearing on themagnification of FIG. 4, where M represents the mesh coming from a frontlap AV and forming a double mesh with a mesh m3 of one of the laps ofthe rear wall AR arranged at the forefront.

This image clearly shows that, by means of the cells of generalpolygonal shape defined by the meshes of the various laps, the fabrichas an open-worked structure possessing high porosity along with lowdensity. It also shows that, by virtue of their distribution on thesides of the polygons, the open unblocked meshes give the fabricsubstantially the same possibilities of deformation longitudinally andtransversely, corresponding, in FIG. 4, to the vertical and transversedirections respectively.

1. A three-dimensional open-worked fabric wall reinforcement producedwith monofilaments consisting of a biocompatible material, worked in aweave with open unblocked meshes forming, in the laps respectivelyforming the front and rear walls of the fabric, cells of substantiallypolygonal shape giving this fabric substantially balanced dynamometricbehaviors at least in two perpendicular directions, said laps of thefront and rear walls being connected by means of a bracing,characterized in that the bracing is ensured by the monofilaments (2) ofone of the laps composing one of the walls (AV and AR) of thereinforcement, each of these monofilaments forming, after a constantnumber of rows of meshes in its lap, a mesh M with one of the meshes(m3) of one of the laps of the other wall (AR and AV) of the fabric. 2.The wall reinforcement as claimed in claim 1, characterized in that itsrespectively front (AV) and rear (AR) walls are each formed by two lapsof monofilaments knitted according to the following scale: Front wall:lap a) 0.1.1.1/1.2.2.2/3.4.4.4/5.4.4.4/4.3.3.3/2.1.1.1// lap b)5.4.4.4/4.3.3.3/2.1.1.1/0.1.2.1/1.2.2.2/3.4.4.4// Rear wall: lap c)4.4.5.4/4.4.4.3/3.3.2.1/1.1.0.1/1.1.1.2/2.2.3.4// lap d)1.1.0.1/1.1.1.2/2.2.3.4/4.4.5.4/4.4.4.3/3.3.2.1//
 3. The wallreinforcement as claimed in claim 2, characterized in that themonofilaments (2) used consist of polypropylene and have a dimension ofbetween 0.07 and 0.14 millimeters.
 4. The wall reinforcement as claimedin claim 2, characterized in that the monofilaments (2) used consist ofpolypropylene and have a dimension of 0.10 millimeters.